Most cable network systems are coaxial-based broadband access systems that may take the form of all-coax network systems, hybrid fiber coax (HFC) network systems, or RF over glass (RFOG) network systems. Cable network system designs, including, for example, cable television (CATV) network system designs, typically use a tree-and-branch architecture that permits bi-directional data transmission, including Internet Protocol (IP) traffic between the cable system head-end and customer locations. There is a forward or downstream signal path (from the cable system head-end to the customer location) and a return or upstream signal path (from the customer location back to the cable system head-end). The upstream and the downstream signals occupy separate frequency bands. In the United States, the frequency range of the upstream band is from 5 MHz to 42 MHz, 5 MHz to 65 MHz, 5 MHz to 85 MHz, or 5 MHz to 200 MHz, while the downstream frequency band is positioned in a range above the upstream frequency band.
Customer locations may include, for example, cable network subscriber's premises. Typical signals coming from a subscriber's premises include, for example, set top box DVR/On Demand requests, test equipment data channels, and Internet Protocol output cable modem carriers defined by the Data Over Cable Service Interface Specification (“DOCSIS”), which is one communication standard for bidirectional data transport over a cable network system.
Signal leakage (egress noise, RF emissions, and so on) may occur due to faulty cabling, insufficient shielding, incomplete connections, faulty or worn connectors, during application of certain digital signal processing techniques, and due to other reasons. Signal leakage may be both wasteful to the cable network operators and may interfere with transmission of other signals and operation of nearby devices or networks.